I was with VZW for years (Blackberry...Droid Pro... Trophy), then switched to at&t with the penny sale on Windows phones @ Thanksgiving. Went through 3 Titans (multiple issues including, but not limited to call quality). Ended my 30-day window w/ Samsung Focus S.
Liked the Samsung phone, but had connectivity problems. In early 2012, had to get iPhone, and now have 4s. Never wanted iPhone, never expected to like it, but I LOVE it.
However, not loving the at&t network. We are now HSPA+ (good) - yet I not infrequently get "no service" indicator... or Edge... or one little teeny bar. In more than 10 yrs w/ Verizon, never had a problem - here or while traveling *anywhere*. I am often in convention centers / hotel conf centers where at&t has no signal and Verizon is fine. On every break, people are comparing their signals and borrowing phones.
I am regretting the move to at&t. When NEXT iPhone drops, I will be back w/ Verizon. Having tried the alternative, I will be back and happy to stay there for a while.
For what its worth, hope it helps to have more info from n of 1!